1994 420E Codes Results - PeachParts Mercedes-Benz Forum

pesuazo · #1 12-06-2008, 06:51 PM

Socket 19: 6 and 12
Socket 4 : 22
Socket 6 : 13, 30
Socket 7 : 5, 6, 14
Socket 8 : 5
Socket 30: 2, 4, 8
Socket 17: 1

I read many posts, and it appears some of the solutions to the codes were replacements of the Stop Lamp switch (S9/1) and the Starter lock-out/backup lamp switch, AKA Neutral Safety Switch (S16/1-3).

JimF's website provides a wealth of helpful information.

Harness will be rebuilt/replaced in the next couple of months.

What other solutions/troubleshooting techniques have been tried to solve the codes above?

deanyel · #2 12-06-2008, 07:59 PM

I don't believe there is such a thing as a 420E, probably an E420. Not everyone has memorized all the code number descriptions for all the models. It's always a good idea to put the code description in your post, not just the number. You should get a better response.

pesuazo · #3 12-07-2008, 11:12 AM

Diagnostic Module (N59) Socket 19:
6 - Idle speed control inoperative
12 - Heated oxygen sensor heater, open/short circuit

LH-SFI Module (N3/1) Socket 4 :
22 - O2S 1 heater, open/short circuit

ABS w/ASR Control module (N30/1) Socket 6 :
13 - Stop Lamp switch (ASD/ASR)
30 - CAN data line to EA/CC/ISC module (N4/1)

EA/CC/ISC Module (N4/1) Socket 7 :
5 - Stop Lamp switch (S9/1)
6 - Starter lock-out/backup lamp switch (S16/3)
14 - Closed throttle position contact switch (S29/3)

Base Module (N16/1) Socket 8 :
5 - Maximum allowable temperature in module box (F23) exceeded

SRS Control module (N2/2) Socket 30:
2 - SRS control module (N2/2)
4 - Front passenger airbag squib (R12/8)
8 - Voltage supply

Ignition Control Module (N1/3) Socket 17:
1 - No Faults in System

I need to find out if there is a systematic procedure to troubleshoot, given the codes shown above.

Thanks

JimF · #4 12-07-2008, 11:20 AM

Looks like you have an "ASR" and some other problems.

If you haven't reset the codes, do that and then see what comes back.

It could be the ETA which is detailed in Menu#24. If you're lucky it could be fixed by a Stop Lamp Sw or NSS. As you read, i had both go bad but not together.

You probably need to replace the O2 sensor; Bosch rates them about 60K miles, so it could be time to replace it. But first do a reset and see what comes back.

PS: that assumes that you have replaced the wiring harness.

pesuazo · #5 12-07-2008, 04:40 PM

JimF,
First I want to thank you for your great website, the information there is great.

I have not replaced/rebuilt the harness, that is in my "to do" list.
A little background about the car:
I bought this car from the original owner for $1K (175K miles), it was parked under a foot of pine needles, the owner told me he parked it there 3 years ago and never moved it, he could not even remember if there was anything wrong with the car. He gave me the original window sticker ($54,375.00).
Long story short, I drove out (with a friend) to the outer banks (about 140 miles) with a dolly to tow it back to Raleigh, NC. Surprisingly (after an oil and filter change) the car fired right up (with my truck battery), and I drove it home.
It performed very well, I ran it up to 110 MPH, and it pulled like a freight train.
The check engine light came up when I parked it home.
I found out about the harness problem once I started searching for codes and how to pull them.
The original battery was dead (1.5 volts) after the 140 mile drive, which may be a reason for some of the codes (I also read in some posts that low voltage could cause some codes).
The alternator is OK, as it puts out 13.5 - 14 VDC. The car ran all the way home with alternator power alone (old battery installed), which explained some of the apparent electrical gremlins when I started testing all the "luxuries" during the drive (cruise control, heated seats, rear curtain, CD changer, etc...).
Under close inspection, I could see the bare wires around the temp. sensor.
By the way, I detailed the interior, and it looks brand new.
I will see if I can post some pictures.

JimF · #6 12-07-2008, 06:39 PM

Tnx for the run-down on the car . . . makes it much easier to give you some suggestions.

Reset the codes, after replaceing the battery . . .

Your FIRST job is to replace the wiring harness and then the O2 sensor and you might be good to go!

If the ETA is bad, you will get the #6 code and the same codes shown in MENU#24 but with the car sitting that long, it may be just "inactivity".

pesuazo · #7 12-08-2008, 01:54 PM

I just finished reading some other posts and article #24 in your website. And things are starting to make a lot of sense after figuring out how the codes relate to each other. But I have still a few questions.

1.- I see that you got a code 6 on the DM (socket 19 or LED), which is most likely related to the code 2 on the EA/CC/ISC Module (socket 7) and the code 30 on the ABS/ASR module (socket 6).
The code 2 on socket 19 appears to be a "catch all".
But then codes 3, 5 and 6 (socket 19) are codes for each individual component captured in code 2 (also socket 19).

I am just wondering, why didn't you get a code 3 (alone), given that it was the only failure (ETA)?

2.- As I read further down the same page, you did get a code 7 (I assume it is a mistype, it should have been a code 6) for the Starter lock-out/backup lamp switch (S16/3).

In the second case you did get the code for the specific failing component. Code 6, assuming mistype, for the Starter lock-out/backup lamp switch (S16/3). And the code was right on.

I am in the process of removing the engine wiring harness (disconnecting and tagging). I will try to finish all the "desoldering/rewiring/soldering/heat shrinking" by Saturday.

Bought a new battery yesterday. And hopefully will fix the busted/leaking brake hard line on the weekend. After that, I will delete all the codes and take it for a "spirited" 100 mile drive on I-40 and I-95, then I will check what codes reappear.

Where is this switch located?
Closed throttle position contact switch (S29/3)

Finally, on another note:
I pulled a vacuum on the AC system (it was empty), it held for about 4 hours with no change, so I decided to charge the system. The compressor is not coming on, is there something I can do to "trick" the compresor to come on? (assuming the compresor is OK)

I remember reading somewhere to "jump" some switch, but cannot remember the location or name of the switch.

Thanks

JimF · #8 12-08-2008, 04:35 PM

My only comment . . . wait until you actually GET the new wiring harness, then as you remove one connection, reconnect w/ the new one.

That's the best way to do it b/c you may not remember each and every connection plus some cables have to pass thru the firewall and the actual method of removal and re-insertion will be fuzzy.

The codes are as they are . . in the subsequent section (replaced the NSS), I used a different scanner.

pesuazo · #9 02-05-2009, 01:36 PM

It has been a while, and work has taken most of my time. I was able to work on the car last weekend.
Here is the update:
1.- Harness was rebuilt and re-installed
Upon disconnecting and connecting the harness to the injectors, one of the seals started leaking gas really bad.
2.- Removed the fuel rail and installed new seals and cups to all injectors
Got new code on pin 4 (code 27 - Injectors (Y/62) Open/Short Circuit. It made sense, since I removed all the connections. I was able to reset the code.
3.- Got new code after charging the A/C and attempting to run it.
Pin 8 code 8 – A/C Electromagnetic clutch jammed (A9K1) or Poly belt broken. It seems the car needs a new clutch at the compressor. But I will try to figure out a way to place 12V at the clutch to see if it pulls.
4.- Replaced brake light switch, will try to replace Oxygen Sensor this weekend.
5.- Still have the brake fluid leak, hence I have not been able to take it for a long drive. Most likely will leave this job for a shop. As those brake lines appears to be a "PITA" to replace
6.- I was able to clear most of the codes, except code 2 (SRS control module (N2/2)) at socket 30. No matter how many times I try, it does not erase it
7.- For some reason now pin 19 (or the outside diagnostic module LED) does not blink at all after pressing the button for 3 seconds (not even the 1 blink).

The check engine light is on, I assume it is there because of the Oxygen Sensor (although I have no codes). Will see if it goes away after replacing the O2 sensor.

JimF · #10 02-05-2009, 03:27 PM

<6.- I was able to clear most of the codes, except code 2 (SRS control module (N2/2)) at socket 30. No matter how many times I try, it does not erase it>

You need a scanner to reset the SRS system.

<*7.-* For some reason now pin 19 (or the outside diagnostic module LED) does not blink at all after pressing the button for 3 seconds (not even the 1 blink).>

That will happen after the modules get "polled" . .

Larry Delor · #11 02-05-2009, 11:35 PM

The O2 sensor is in a lousy place. Plan on lifting the car up, so that you can drop the exhaust a little, in order to get to the sensor.

It is at an angle, towards the top of the Y.

I think, I remember someone telling me that the throttle position contact switch is inside of the ETA. Many ETA's suffer(ed) from substandard wiring insulation as well.

Will_w202 · #12 02-06-2009, 05:44 PM

Check PM

If the harness is now good, then the ETA is probably the next culprit. You can try replacing the cheaper stuff first, but ETAs are known failure points. The o2 sensor will strip before you can get it off, unless you use alternating heat and cold (torch and cold water). Use a mirror, mark it and make sure you are getting movement else you will need the special tool to dremel it out! Taillight assembly contacts get corroded, causing ASR lights and limp mode. You can swap them with used parts or repair the contacts. Don't forget the wheel speed sensors, which can cause gremlins as well.

pesuazo · #13 02-09-2009, 08:25 AM

[QUOTE=Will_w202;2102275]Check PM
The o2 sensor will strip before you can get it off, unless you use alternating heat and cold (torch and cold water). Use a mirror, mark it and make sure you are getting movement else you will need the special tool to dremel it out! QUOTE]

Right on the money!!!
Even though I have the O2 sensor remover socket, it still stripped!!!
I remember some one wrote that the O2 sensor location was picked by Satan, I could not help burst in laughter when I was trying to remove it.

It became:

Mission impossible!!

It will stay there until I can figure something out.

What is the special tool to dremel it out?

pesuazo · #14 04-03-2009, 01:34 PM

It has been about 2 months, so I decided to update.

I have had 3 LH modes in all this time (it happens, but about once every other week). A restart takes it away.

I still have the Check Engine Light, I know, the O2 sensor (still cannot get it out, will give it another shot this weekend).

These are the codes I am getting after 2K miles.

LH-SFI Module (N3/1) Socket 4:
22 - O2S 1 heater, open/short circuit

ABS w/ASR Control module (N30/1) Socket 6:
30 - CAN data line to EA/CC/ISC module (N4/1)

EA/CC/ISC Module (N4/1) Socket 7:
6 - Starter lock-out/backup lamp switch (S16/3)

14 - Closed throttle position contact switch (S29/3)

Base Module (N16/1) Socket 8:
10 - Base module (N16/1) voltage supply output fuse F2 open circuit
11 - Base module (N16/1) voltage supply output fuse F3 open circuit
12 - Base module (N16/1) voltage supply output fuse F1 open circuit
13 - Base module (N16/1) voltage supply output fuse F4 open circuit

Ignition Control Module (N1/3) Socket 17:
1 - No Faults in System

Diagnostic Module (N59) Socket 19:
6 - Idle speed control inoperative

12 - Heated oxygen sensor heater, open/short circuit

SRS Control module (N2/2) Socket 30:
9 - SRS warning lamp (A1e15) or insufficient time to read out the DTC memory or erase DTCs

Somewhat different from the last time. I replaced the brake line and the brake light switch.

Socket 8 codes are BS, as all the fuses are OK.

I will erase all codes and drive for a week to see what comes back. I know for sure the O2 will be back (22 on socket 4 and 12 on 19)

The only thing to replace is the NSS, but I will not do it unless LH becomes a REAL problem (more than once a day).

david s poole · #15 04-03-2009, 02:00 PM

i think you can get rid of a lot of those codes by replacing the electronic accel with a rebuilt.the wiring in the pigtail connector will be toast as well as the internal wiring.